1. Field
The present invention relates generally to the railroad field and more particularly to devices, systems and methods for improving fuel efficiency in locomotive consists.
2. Discussion of the Background
A locomotive consist is a group of locomotives physically coupled together and configured to act as a single unit from the controls of a single locomotive in the consist. In the U.S., the operation of multiple locomotives in this manner is often referred to as multiple unit, or “MU”, operation. In this mode, the throttle setting (also referred to as the throttle notch) in the lead locomotive, which may not be the first locomotive in the consist, controls the throttle setting or notch in all locomotives in the consist. A locomotive throttle typically has eight notches and an idle position. Thus, for example, if an operator in a lead locomotive in an MU consist puts the throttle into notch 5, then every other locomotive in the consist will also operate at a notch 5 throttle setting (it should be understood that the actual throttle may or may not move, but that the control signals supplied to the locomotive power plant will correspond to a notch 5 throttle setting).
It has been recognized that the operation of all locomotives in a consist in the same throttle setting is not always fuel efficient. Many locomotives are more efficient at higher notch settings. Thus, it may be more fuel efficient for some of the locomotives in a consist to operate at a higher notch setting than that set by the operator while others in the consist operate at a lower setting. For example, in a three locomotive consist, it may be more fuel efficient for two of the locomotives to operate in notch 8 with the third in neutral rather than all three locomotives operating in notch 5, assuming that the total power is approximately the same.
Others have devised systems and methods for improving fuel efficiency. Such systems include U.S. Pat. Nos. 4,344,364 and 6,691,957. Such systems are less than optimal.